More the defective genes, worse is the constitution. Such a person suffers from severe diseases & dies a premature death. The constitution that is resistance is constantly modified by diet, rest, activity, happiness, sorrow and environmental factors.
The character of the fever gives us an idea about the dosha which is affected. Irregular fever, high fever & mild fever indicate increase in vata, pitta and kapha doshas respectively.
On the other hand the aetiological factors, causative doshas and pathogenesis are different when a new disease is super-imposed on the first disease.
Premonitory symptoms are classified as general and specific premonitory symptoms. They are related to dosha, which is increased in that disease.
When aetiological factors are not controlled and continue to act for long the doshas continue to increase further and accumulate in excess until they reach the prakopa stage.
Particular epidemic affects only a particular region and takes toll of lives of masses. Ayurveda ascribes the epidemics to non-religious behaviour and the sinful acts of the masses.
Most authorities feel that affection by grahas is a result of bad deeds of the past life of the same individual. These grahas do not enter the body of child themselves, but affect the babies through their innumerable, microscopic followers, which thrive on blood, fat, muscles, etc. of the baby.
There is a subtle-world much more vast than the physical world and Incidents taking place in this world affect the health of human beings too. Ayurveda calls these subtle aspects ‘grahas’.
Our Saints and Sages have conducted detailed studies on disease-causing germs thousands of years ago. The germs play a very important role in pathogenesis of a disease.
Fasting is indicated, when Aama doshas have accumulated in the tissues as in states of toxaemia. Get rid of Aama by stimulating the tissue enzymes, which would digest Aama locally–